The invention relates to devices that minimize the pollution of operating rooms with anesthesia gases. More particularly, the invention relates to devices that prevent anesthesia gases from escaping from anesthesia circuit fittings during periods in which the anesthetic circuit is not attached to a patient's airway or to an airway securement device.
Surgical procedures often require the administration of a general anesthesia to a patient. In many instances the anesthesia is delivered with a gas through an anesthesia mask that is applied over a patient's nose and mouth. Recent reports indicate that the atmosphere within operating rooms during surgical procedures often contains potentially harmful levels, as much as 12 to 40 times the NIOSH recommended limit, of volatile anesthetic vapor and nitrous oxide gas. Studies have suggested that chronic exposure to trace levels of anesthetic gas is harmful to operating room personnel. Exposure to nitrous oxide causes decreased mental performance, audio-visual ability, and manual dexterity. It is also believed that exposure to high levels of nitrous oxide in the workplace can cause reduced fertility, spontaneous abortions, and neurologic, renal and liver disease. See, Anesthesiology News, October 1994.
Standard anesthesia procedures utilize an anesthesia machine to deliver an anesthetic gas mixture through an anesthesia circuit, attached to a mask or other airway securement device, such as an endotracheal tube (ETT) or laryngeal mask airway (LMA), to the patient. Initially, the anesthesia machine delivers oxygen to preoxygenate the patient. Then the machine adds the anesthetic vapor and nitrous oxide gas to the oxygen stream. When the patient is sufficiently anesthetized, the anesthetic gas supply is shut off and, in order to intubate the patient with an airway securement device, the mask is removed from the patient's face and often simply laid open on a convenient surface. During the time interval between the removal of the mask and the reconnection of the circuit fittings to the emplaced ETT or LMA, the flow of oxygen continues from the anesthesia machine directly into the operating room atmosphere. The oxygen is not pure, however. Although the supply of anesthetic gases has been shut down at the anesthesia machine, residual gases continue to be swept out by the oxygen flow. Because of the time constants of anesthetic elimination from the circuit, as much as 16 minutes can elapse before this release of residual anesthetic gases to the operating room environment is reduced to negligible levels. It is this release of the residual anesthetic gases which creates the hazards to operating room personnel.
Since it is necessary to use anesthetic circuits for anesthesia delivery, steps must be taken to reduce the dangers presented to operating room personnel through such techniques. At the same time, care must be taken not to compromise the operation and performance of the anesthesia circuit.
Accordingly, it is an object of the invention to provide a device to prevent the unintended pollution of operating rooms with anesthesia gases. A further object is to provide such a device that conveniently supports an anesthesia delivery mask and an anesthesia circuit fitting while preventing the escape of gas into the operating room environment. Another object of the invention is to provide such a device that does not alter the structure of or affect the performance of the anesthesia circuit. It is also an object to provide a device that enables an anesthesiologist to remove with greater ease an anesthesia delivery mask from an anesthetic circuit fitting. These and other objects will be apparent upon reading the description that follows.